19
respectively, mean that a doubling of expected sightings would yield 6% and 10%
increases in trips taken to Point Reyes and Monterey, respectively.
A final point about the estimation results concerns the marginal value of time,
which is significant at the 10% level (1-tailed test) in Table 3. This parameter was
estimated with a squared transformation to impose the requirement that the marginal
value of time is nonnegative, and the estimate of -0.7778 implies that the relative
marginal value of time is .605 for everyone (Table 5). Rescaling by the ratio of deflators
M/T, the absolute marginal value of time is, on average, $5.87 per hour, and varies from
a low of $0.45/hr. to a high of $13.60/hr. in the sample.
Access value estimates are presented in Table 6. The consumer's surplus
estimates of willingness to pay for access at prevailing price conditions are $779 for
Point Reyes and $129 for Monterey, while the compensating variation estimates are $834
and $126, respectively. The magnitudes of the Hicksian and Marshallian measures are
close, reflecting a small overall income effect at each site, despite the fact that demands
are income elastic; also, the compensating variation measure is larger at Point Reyes,
since it is a normal good, while consumer's surplus is larger at Monterey, because of its
negative income effect. Measured relative to the mean number of trips, the access value
on a per trip basis is approximately $779/2.16 ≈ $360/trip at Point Reyes, and about
$129/1.64 ≈ $79/trip at Monterey. While the range in per-trip values may seem a bit
large, in fact it is consistent with the difference in prices of whalewatching and in income
elasticities at the two sites. Because most trips in Monterey are taken on boats, the price
of a whalewatching trip is higher than at Point Reyes; because of this, access value will
be lower at Monterey, all else equal. Similarly, the pattern of visitation being heavier
among those with lower leisure budgets at Monterey suggests willingness to pay is lower.